Evolution and Mechanism of P-GaN Films Under Proton Irradiation and Its Influence on Electronic Device

Abstract

Electrical and optical properties deterioration of P-GaN films under 150 keV proton irradiation were investigated. Through the Hall measurement method, as the irradiation fluence increasing, the carrier concentration of P-GaN films decreases from 1.23×1017 to -8.24×1016 cm-3, and the carrier mobility change from 5.64 to 295.84 cm2/V/s. And through the circular transmission line model method, the sheet resistance and specific contact resistance for PGaN films increased first and then decreased slightly under the proton irradiation. Radiation-induced VN, Gai, VGa and Ni were found to be responsible for the degradation of P-GaN films. It was confirmed that P-GaN has been transformed into N-GaN under the fluence of 1×1015 p/cm2. The optical properties of the P-GaN films were characterized by examining changes in the photoluminescence spectrum. In addition, the electrical characteristics of SBD and PIN diodes with the same structure (except for 0.5 μm P-GaN of PIN diode) were used to study the effect of P-GaN degradation on electronic device performance. When P-GaN was transformed into N-GaN, PIN diodes lost the electrical characteristics of the PN junction and the IV curves of PIN diode are similar to that with SBD.